From 14bb08c1df8db9ec6c8a05520d4eee67971235d9 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Thu, 27 Sep 2018 20:03:23 +0200 Subject: mod tidy --- vendor/golang.org/x/image/webp/decode.go | 272 ------------------------------- 1 file changed, 272 deletions(-) delete mode 100644 vendor/golang.org/x/image/webp/decode.go (limited to 'vendor/golang.org/x/image/webp/decode.go') diff --git a/vendor/golang.org/x/image/webp/decode.go b/vendor/golang.org/x/image/webp/decode.go deleted file mode 100644 index 111f358..0000000 --- a/vendor/golang.org/x/image/webp/decode.go +++ /dev/null @@ -1,272 +0,0 @@ -// Copyright 2011 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// +build go1.6 - -package webp - -import ( - "bytes" - "errors" - "image" - "image/color" - "io" - - "golang.org/x/image/riff" - "golang.org/x/image/vp8" - "golang.org/x/image/vp8l" -) - -var errInvalidFormat = errors.New("webp: invalid format") - -var ( - fccALPH = riff.FourCC{'A', 'L', 'P', 'H'} - fccVP8 = riff.FourCC{'V', 'P', '8', ' '} - fccVP8L = riff.FourCC{'V', 'P', '8', 'L'} - fccVP8X = riff.FourCC{'V', 'P', '8', 'X'} - fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'} -) - -func decode(r io.Reader, configOnly bool) (image.Image, image.Config, error) { - formType, riffReader, err := riff.NewReader(r) - if err != nil { - return nil, image.Config{}, err - } - if formType != fccWEBP { - return nil, image.Config{}, errInvalidFormat - } - - var ( - alpha []byte - alphaStride int - wantAlpha bool - widthMinusOne uint32 - heightMinusOne uint32 - buf [10]byte - ) - for { - chunkID, chunkLen, chunkData, err := riffReader.Next() - if err == io.EOF { - err = errInvalidFormat - } - if err != nil { - return nil, image.Config{}, err - } - - switch chunkID { - case fccALPH: - if !wantAlpha { - return nil, image.Config{}, errInvalidFormat - } - wantAlpha = false - // Read the Pre-processing | Filter | Compression byte. - if _, err := io.ReadFull(chunkData, buf[:1]); err != nil { - if err == io.EOF { - err = errInvalidFormat - } - return nil, image.Config{}, err - } - alpha, alphaStride, err = readAlpha(chunkData, widthMinusOne, heightMinusOne, buf[0]&0x03) - if err != nil { - return nil, image.Config{}, err - } - unfilterAlpha(alpha, alphaStride, (buf[0]>>2)&0x03) - - case fccVP8: - if wantAlpha || int32(chunkLen) < 0 { - return nil, image.Config{}, errInvalidFormat - } - d := vp8.NewDecoder() - d.Init(chunkData, int(chunkLen)) - fh, err := d.DecodeFrameHeader() - if err != nil { - return nil, image.Config{}, err - } - if configOnly { - return nil, image.Config{ - ColorModel: color.YCbCrModel, - Width: fh.Width, - Height: fh.Height, - }, nil - } - m, err := d.DecodeFrame() - if err != nil { - return nil, image.Config{}, err - } - if alpha != nil { - return &image.NYCbCrA{ - YCbCr: *m, - A: alpha, - AStride: alphaStride, - }, image.Config{}, nil - } - return m, image.Config{}, nil - - case fccVP8L: - if wantAlpha || alpha != nil { - return nil, image.Config{}, errInvalidFormat - } - if configOnly { - c, err := vp8l.DecodeConfig(chunkData) - return nil, c, err - } - m, err := vp8l.Decode(chunkData) - return m, image.Config{}, err - - case fccVP8X: - if chunkLen != 10 { - return nil, image.Config{}, errInvalidFormat - } - if _, err := io.ReadFull(chunkData, buf[:10]); err != nil { - return nil, image.Config{}, err - } - const ( - animationBit = 1 << 1 - xmpMetadataBit = 1 << 2 - exifMetadataBit = 1 << 3 - alphaBit = 1 << 4 - iccProfileBit = 1 << 5 - ) - if buf[0] != alphaBit { - return nil, image.Config{}, errors.New("webp: non-Alpha VP8X is not implemented") - } - widthMinusOne = uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16 - heightMinusOne = uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16 - if configOnly { - return nil, image.Config{ - ColorModel: color.NYCbCrAModel, - Width: int(widthMinusOne) + 1, - Height: int(heightMinusOne) + 1, - }, nil - } - wantAlpha = true - - default: - return nil, image.Config{}, errInvalidFormat - } - } -} - -func readAlpha(chunkData io.Reader, widthMinusOne, heightMinusOne uint32, compression byte) ( - alpha []byte, alphaStride int, err error) { - - switch compression { - case 0: - w := int(widthMinusOne) + 1 - h := int(heightMinusOne) + 1 - alpha = make([]byte, w*h) - if _, err := io.ReadFull(chunkData, alpha); err != nil { - return nil, 0, err - } - return alpha, w, nil - - case 1: - // Read the VP8L-compressed alpha values. First, synthesize a 5-byte VP8L header: - // a 1-byte magic number, a 14-bit widthMinusOne, a 14-bit heightMinusOne, - // a 1-bit (ignored, zero) alphaIsUsed and a 3-bit (zero) version. - // TODO(nigeltao): be more efficient than decoding an *image.NRGBA just to - // extract the green values to a separately allocated []byte. Fixing this - // will require changes to the vp8l package's API. - if widthMinusOne > 0x3fff || heightMinusOne > 0x3fff { - return nil, 0, errors.New("webp: invalid format") - } - alphaImage, err := vp8l.Decode(io.MultiReader( - bytes.NewReader([]byte{ - 0x2f, // VP8L magic number. - uint8(widthMinusOne), - uint8(widthMinusOne>>8) | uint8(heightMinusOne<<6), - uint8(heightMinusOne >> 2), - uint8(heightMinusOne >> 10), - }), - chunkData, - )) - if err != nil { - return nil, 0, err - } - // The green values of the inner NRGBA image are the alpha values of the - // outer NYCbCrA image. - pix := alphaImage.(*image.NRGBA).Pix - alpha = make([]byte, len(pix)/4) - for i := range alpha { - alpha[i] = pix[4*i+1] - } - return alpha, int(widthMinusOne) + 1, nil - } - return nil, 0, errInvalidFormat -} - -func unfilterAlpha(alpha []byte, alphaStride int, filter byte) { - if len(alpha) == 0 || alphaStride == 0 { - return - } - switch filter { - case 1: // Horizontal filter. - for i := 1; i < alphaStride; i++ { - alpha[i] += alpha[i-1] - } - for i := alphaStride; i < len(alpha); i += alphaStride { - // The first column is equivalent to the vertical filter. - alpha[i] += alpha[i-alphaStride] - - for j := 1; j < alphaStride; j++ { - alpha[i+j] += alpha[i+j-1] - } - } - - case 2: // Vertical filter. - // The first row is equivalent to the horizontal filter. - for i := 1; i < alphaStride; i++ { - alpha[i] += alpha[i-1] - } - - for i := alphaStride; i < len(alpha); i++ { - alpha[i] += alpha[i-alphaStride] - } - - case 3: // Gradient filter. - // The first row is equivalent to the horizontal filter. - for i := 1; i < alphaStride; i++ { - alpha[i] += alpha[i-1] - } - - for i := alphaStride; i < len(alpha); i += alphaStride { - // The first column is equivalent to the vertical filter. - alpha[i] += alpha[i-alphaStride] - - // The interior is predicted on the three top/left pixels. - for j := 1; j < alphaStride; j++ { - c := int(alpha[i+j-alphaStride-1]) - b := int(alpha[i+j-alphaStride]) - a := int(alpha[i+j-1]) - x := a + b - c - if x < 0 { - x = 0 - } else if x > 255 { - x = 255 - } - alpha[i+j] += uint8(x) - } - } - } -} - -// Decode reads a WEBP image from r and returns it as an image.Image. -func Decode(r io.Reader) (image.Image, error) { - m, _, err := decode(r, false) - if err != nil { - return nil, err - } - return m, err -} - -// DecodeConfig returns the color model and dimensions of a WEBP image without -// decoding the entire image. -func DecodeConfig(r io.Reader) (image.Config, error) { - _, c, err := decode(r, true) - return c, err -} - -func init() { - image.RegisterFormat("webp", "RIFF????WEBPVP8", Decode, DecodeConfig) -} -- cgit v1.2.3